1 Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
2 Institute of Pathology, Ludwig-Maximilians-Universität München, Munich, Germany.
3 Dana Farber/Boston Children's Cancer and Blood Disorders Center, Harvard Medical School, Boston, MA, USA.
4 Department of Pediatrics and Adolescent Medicine, Aarhus University Hospital, Aarhus, Denmark.
5 Department of Pediatrics, UCSF Benioff Children's Hospital San Francisco, University of California, San Francisco, CA, USA.
6 Department of Medicine, Section of Hematology/Oncology, The University of Chicago, Chicago, IL, USA.
7 Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
8 Department of Pathology, Texas Tech University Health Sciences Center, El Paso, TX, USA.
9 Hematology Section, Department of Laboratory Medicine, National Institutes of Health Clinical Center, Bethesda, MD, USA. calvok@cc.nih.gov.